The invention relates generally to hydraulic steering systems and, more particularly, to a system and method for selectively charging and discharging a steering accumulator.
Power steering systems allow an operator to turn a steering wheel of a motorized vehicle with greater torque than in systems without power steering. Thus, a vehicle equipped with power steering is easier to maneuver than the same type of vehicle without power steering. In certain vehicles, such as certain agricultural vehicles, off-road vehicles, work vehicles, and the like, turning a steering wheel without power steering may be very difficult. Many vehicle power steering systems are hydraulically based, particularly in such large vehicle applications. In hydraulically based power steering systems, a hydraulic pump generally pumps hydraulic fluid to be used by the power steering system. As may be appreciated, certain faults may occur in power steering systems that cause the systems to not function properly. For example, the hydraulic pump may stop functioning, a control unit may not work properly, an engine failure may occur, or hoses carrying hydraulic fluid may leak.
To overcome certain power steering problems, power steering systems may use an accumulator to store a supply of pressurized hydraulic fluid that can be used as a backup if pressure from the main hydraulic fluid supply drops too low. In such systems, the accumulator may be charged while the hydraulic system is functioning properly. If a problem is detected, the power steering system switches from using the main hydraulic fluid supply to the backup hydraulic fluid supply from the accumulator. This allows a vehicle operator to maneuver the vehicle for a short period of time, such as for moving the vehicle from a location on a road to a roadside or parked location. However, known power steering systems implement accumulator charging and/or discharging in an inefficient manner. Accordingly, there exists a need for steering accumulator charging systems that efficiently charge and/or discharge the steering accumulator.